全文获取类型
收费全文 | 2593篇 |
免费 | 295篇 |
国内免费 | 534篇 |
专业分类
安全科学 | 309篇 |
废物处理 | 46篇 |
环保管理 | 370篇 |
综合类 | 1686篇 |
基础理论 | 311篇 |
污染及防治 | 163篇 |
评价与监测 | 316篇 |
社会与环境 | 149篇 |
灾害及防治 | 72篇 |
出版年
2024年 | 8篇 |
2023年 | 64篇 |
2022年 | 98篇 |
2021年 | 110篇 |
2020年 | 96篇 |
2019年 | 93篇 |
2018年 | 85篇 |
2017年 | 111篇 |
2016年 | 126篇 |
2015年 | 140篇 |
2014年 | 141篇 |
2013年 | 183篇 |
2012年 | 245篇 |
2011年 | 202篇 |
2010年 | 156篇 |
2009年 | 135篇 |
2008年 | 120篇 |
2007年 | 154篇 |
2006年 | 164篇 |
2005年 | 153篇 |
2004年 | 114篇 |
2003年 | 129篇 |
2002年 | 77篇 |
2001年 | 72篇 |
2000年 | 82篇 |
1999年 | 63篇 |
1998年 | 46篇 |
1997年 | 53篇 |
1996年 | 47篇 |
1995年 | 35篇 |
1994年 | 22篇 |
1993年 | 20篇 |
1992年 | 20篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3422条查询结果,搜索用时 906 毫秒
101.
煤矿局部通风机(简称“局扇”)的噪声是煤矿掘进中的主要噪声源,分析了局扇噪声的产生机理,提出了减少局扇的动叶叶顶与机壳间隙,在局扇入口加阻性消声器和在机壳涂上一层阻尼材料等方法来控制局扇的噪声方法,方法在JBT52-2型局扇的试验研究表明,实施上海降噪措施,局扇的噪声有大幅度降低,可使局扇的噪声达到工矿企业噪声卫生标准要求。 相似文献
102.
103.
104.
根据油气集输泵站稳定压缩机泵房噪声污染的现状,提出了采用空间吸声体降低噪声和采用田声降低噪声的技术方案,分析了实施后的效果和推广应用前景。 相似文献
105.
106.
107.
探讨了国内外20种护耳器对石油钻井噪声的防护效果。首先在隔声室内模拟石油钻井工人接触的噪声环境,声级达103dB(A)。采用护耳器主观测量方法对每种护耳器进行噪声防护效果测量,并筛选出噪声防护效果明显的几种护耳器。 相似文献
108.
本文阐述了地下水污染潜势评估的重要性,介绍了三种方法,对其中的废物-土址-地点相互作用列表法作了详细介绍,并将WSSIM法用于四川省什邡县化工开发区地下不污染潜势估。 相似文献
109.
This paper assesses the status of coastal zones in the context of expected climate change and its related impacts, as well as current and future socioeconomic pressures and impacts. It is argued that external stresses and shocks relating to sea-level rise and other changes will tend to exacerbate existing environmental pressures and damage in coastal zones. Coastal zones are under increasing stress because of an interrelated set of planning failures including information, economic market, and policy intervention failures. Moves towards integrated coastal zone management are urgently required to guide the coevolution of natural and human systems. Overtly technocentric claims that assessments of vulnerability undertaken to date are overestimates of likely future damages from global warming are premature. While it is the case that forecasts of sea-level rise have been scaled down, much uncertainty remains over, for example, combined storm, sea surge, and other events. In any case, within the socioeconomic analyses of the problem, resource valuations have been at best only partial and have failed to incorporate sensitivity analysis in terms of the discount rates utilized. This would indicate an underestimation of potential damage costs. Overall, a precautionary approach is justified based on the need to act ahead of adequate information acquisition, economically efficient resource pricing and proactive coastal planning. 相似文献
110.
Mechanical Properties with the Functional Group of Additives for Starch/PVA Blend Film 总被引:1,自引:0,他引:1
This paper deals with the mechanical properties and degree of swelling (DS) of starch/PVA blend film with the functional groups
i.e., hydroxyl and carboxyl group, of additives. Starch/PVA blend films were prepared by using the mixing process. Glycerol
(GL) with 3 hydroxyl group, sorbitol (SO) with 6 hydroxyl group, succinic acid (SA) with 2 carboxyl group, malic acid (MA)
with 1 hydroxyl and 2 carboxyl group, tartaric acid (TA) with 2 hydroxyl and 2 carboxyl group and citric acid (CA) with 1
hydroxyl and 3 carboxyl group were used as additives. The results of measured tensile strength (TS) and elongation (%E) verified
that both hydroxyl and carboxyl group as a functional groups increased the flexibility and strength of the film. Values of
DS for GL-added and SA-added films were low. However, DS values of the films added MA, TA or CA with both hydroxyl and carboxyl
group were comparatively high. When the film was dried at low temperature, the properties of the films were evidently improved.
The reason is probably because the hydrogen bonding was activated at low temperature. 相似文献